[Sony Xperia M] tarkan-t29:
Hello everyone,

Edit: Solved the problem by using the version (0.9.18.6) of FlashTool.

So, I tried to rollback the phone into the Stock ROM, downloaded the latest Flashtool, downloaded the latest FTF ROM (C1905 15.4.A.0.23) but when I try to flash it with Flashtool, it asks me to shut the phone off, long press the Vol - button and put the USB cable, it starts to flash then abords... When I pull off the USB cable and try to boot up, I come again to CM12.1 like nothing happened.

Here is the log of my Flashtool :

08/008/2016 01:08:49 - INFO - Flashtool Version 0.9.19.8 built on 24-09-2015 22:00:00
08/008/2016 01:08:49 - INFO - libusb version 1.0.20
08/008/2016 01:08:49 - INFO - Executing search strategies to find proxy selector
08/008/2016 01:08:49 - INFO - No proxy found for gnome. Trying next one
08/008/2016 01:08:49 - INFO - No proxy found for kde. Trying next one
08/008/2016 01:08:49 - INFO - Strategy firefox failed trying next one : No Firefox installation found
08/008/2016 01:08:49 - INFO - Syncing devices from github
08/008/2016 01:08:49 - INFO - Scanning devices folder for changes.
08/008/2016 01:08:54 - INFO - Pulling changes from github.
08/008/2016 01:08:55 - INFO - Devices sync finished.
08/008/2016 01:08:55 - INFO - Device disconnected
08/009/2016 01:09:34 - INFO - Selected Bundle for Sony Xperia M (C1905). FW release : 15.4.A.0.23. Customization : Generic PL
08/009/2016 01:09:34 - INFO - Preparing files for flashing
08/009/2016 01:09:52 - INFO - Please connect your device into flashmode.
08/010/2016 01:10:01 - INFO - Device connected in flash mode
08/010/2016 01:10:06 - INFO - Opening device for R/W
08/010/2016 01:10:06 - INFO - Device ready for R/W.
08/010/2016 01:10:06 - INFO - Reading device information
08/010/2016 01:10:06 - INFO - Phone ready for flashmode operations.
08/010/2016 01:10:06 - INFO - Opening TA partition 2
08/010/2016 01:10:06 - INFO - Current device : Unknown: May 9 2014/12:58:25 - YT910RMRFU - Unknown: May 9 2014/12:58:25 - Unknown: May 9 2014/12:58:25 - Unknown: May 9 2014/12:58:25
08/010/2016 01:10:06 - INFO - Closing TA partition
08/010/2016 01:10:06 - INFO - Start Flashing
08/010/2016 01:10:06 - INFO - Processing loader.sin
08/010/2016 01:10:06 - INFO - Checking header
08/010/2016 01:10:06 - INFO - Flashing data
08/010/2016 01:10:07 - INFO - Loader : S1_Root_dbe9 - Version : loader_MSM8X30_10 / Boot version : S1_Boot_MSM_8227_5 / Bootloader status : ROOTED
08/010/2016 01:10:07 - INFO - Max packet size forced to 256K
08/010/2016 01:10:07 - INFO - Making a TA backup
08/010/2016 01:10:07 - INFO - Opening TA partition 1
08/010/2016 01:10:07 - INFO - Start Dumping TA partition 1
08/010/2016 01:10:07 - INFO - Finished Dumping TA partition 1
08/010/2016 01:10:07 - INFO - TA partition 1 saved to /root/.flashTool/registeredDevices/YT910RMRFU/s1ta/2016-02-07_01-10-07/1.ta
08/010/2016 01:10:07 - INFO - Closing TA partition
08/010/2016 01:10:07 - INFO - Opening TA partition 2
08/010/2016 01:10:07 - INFO - Start Dumping TA partition 2
08/010/2016 01:10:07 - INFO - Finished Dumping TA partition 2
08/010/2016 01:10:07 - INFO - TA partition 2 saved to /root/.flashTool/registeredDevices/YT910RMRFU/s1ta/2016-02-07_01-10-07/2.ta
08/010/2016 01:10:07 - INFO - Closing TA partition
08/010/2016 01:10:07 - INFO - Parsing boot delivery
08/010/2016 01:10:07 - INFO - Ending flash session
08/010/2016 01:10:07 - ERROR -
08/010/2016 01:10:07 - ERROR - Error flashing. Aborted
08/010/2016 01:10:07 - INFO - Device connected in flash mode

Additional infos :

Using CM12.1 (12.1-20160116) with NUI Kernel 6.0r2

Tried with 3 Data USB cables I use daily for file transfer and so on

Tried to remove Flastool and retry

Tried with other FTF files

Using Ubuntu Gnome 15.14

Thanks in advance for your help :)